24 THE VENOMS OF CERTAIN THANATOPHIDE^E. 



dead, but finally recovered in the seventh experiment and in the subsequent ones 

 there were no poisonous symptoms. It will thus be observed that there is a gradual 

 impairment of the toxicity of the venom increasing with the increase of tempera- 

 ture, and that when we reach 76.5 C. we have almost reached the temperature at 

 which toxicity seems to be completely destroyed. We say seems completely 

 destroyed, because we have found that the solution is still toxic even when boiled, 

 although there is not sufficient active poisonous matter left after boiling in the 

 small amount of venom we used in this group of observations to cause decidedly 

 poisonous effects in pigeons. 



The results of boiling solutions of Moccasin and Cobra, venoms are quite different 

 from the above, as the following experiments clearly show: 



Experiment. Dissolved 0.015 gram dried Moccasin in 1 c. c. distilled water, 

 and gradually heated to 78 C. 



3:40. Injected into the breast of a pigeon. 

 3:50. Rocking. 



4:45. Nearly gone; some local effect. 



Following morning the animal was dead. The local effect (darkening) was marked, but 

 not comparable to that caused by the unboiled venom. 



Experiment. Boiled 0.015 gram dried Moccasin (piscivoris) dissolved in 1 c. c. 

 distilled water for one minute. 



3:28. Injected the above into the breast muscles of a pigeon. 



3:35. Too weak to stand. 



4:15. Dead. There are no local effects. 



Experiment. Dissolved about 1| minims of fresh Moccasin venom in about 1 

 c. c. distilled water, then boiled in a test-tube, filtered and injected one-half into 

 the breast muscles of a pigeon at 4:30. 



4:55. Very slight local effect; darkening and swelling; the animal is weak and has respi- 

 ratory disturbance. 



Injected the other half. 



5:00. Rocking; irregular breathing ; somewhat stupefied. 



5:20. Eyes closed; stupefied; breathing irregular. 



Following morning. There was a large, light-colored, oadematous swelling (see Plate No. 1) 

 within, which was a cavity about an inch in diameter, full of broken-down tissue, having a 

 grayish muddy, gangrenous appearance, and a putrefactive odor, while the surrounding 

 muscular tissues were normal in appearance. 



It will be observed in this series of experiments with the Moccasin venom that 

 there is also a very decided alteration in the poisonous properties of the venom. 

 But here we find that although the amount of venom used was only one-half the 

 quantity employed in the Crotalus series, boiling does not destroy its ability to 

 kill. It will also be noticed here, as in the case of the Crotalus, that a sufficient 

 degree of heat has an obvious effect on the power of the venom to produce the 

 peculiar lesions at the point of injection. 



The effect of heat upon solutions of Cobra venom is not so marked. 



Experiment. 0.03 gram dried Cobra venom was dissolved in 1 c. c. distilled 

 water and subjected to a temperature gradually rising to 74 C. 



4:10. Injected into the breast muscles of a pigeon. 

 4:16. Unable to stand. 

 4:20. Dead. 



